MSR_IA32_SPEC_CTRL is not available unless CPU[7,0].EDX[26] is 1. Check that against host CPUID or guest CPUID, respectively for host-initiated and guest-initiated accesses. Suggested-by: Jim Mattson <jmattson@xxxxxxxxxx> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> --- This is for after X86_FEATURE_SPEC_CTRL is added to Linux, but I still wanted to ack Jim's improvement. arch/x86/kvm/svm.c | 8 ++++++++ arch/x86/kvm/vmx.c | 8 ++++++++ 2 files changed, 16 insertions(+) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 97126c2bd663..3a646580d7c5 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -3648,6 +3648,10 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) msr_info->data = svm->nested.vm_cr_msr; break; case MSR_IA32_SPEC_CTRL: + if (!static_cpu_has(X86_FEATURE_SPEC_CTRL) || + (!msr_info->host_initiated && + !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))) + return 1; msr_info->data = svm->spec_ctrl; break; case MSR_IA32_UCODE_REV: @@ -3806,6 +3810,10 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) vcpu_unimpl(vcpu, "unimplemented wrmsr: 0x%x data 0x%llx\n", ecx, data); break; case MSR_IA32_SPEC_CTRL: + if (!static_cpu_has(X86_FEATURE_SPEC_CTRL) || + (!msr_info->host_initiated && + !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))) + return 1; svm->spec_ctrl = data; break; case MSR_IA32_APICBASE: diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 49b4a2d61603..42bc7ee293e4 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -3368,6 +3368,10 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) msr_info->data = guest_read_tsc(vcpu); break; case MSR_IA32_SPEC_CTRL: + if (!static_cpu_has(X86_FEATURE_SPEC_CTRL) || + (!msr_info->host_initiated && + !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))) + return 1; msr_info->data = to_vmx(vcpu)->spec_ctrl; break; case MSR_IA32_SYSENTER_CS: @@ -3510,6 +3514,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) kvm_write_tsc(vcpu, msr_info); break; case MSR_IA32_SPEC_CTRL: + if (!static_cpu_has(X86_FEATURE_SPEC_CTRL) || + (!msr_info->host_initiated && + !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))) + return 1; to_vmx(vcpu)->spec_ctrl = data; break; case MSR_IA32_CR_PAT: -- 1.8.3.1
